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0Cr2+ - Fe2+ ions interaction in ZnSe based solid solutions
M.E. Doroshenko1*, H. Jelinkova2
1-Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991, Vavilov Str. 38,
Moscow, Russia
2- Czech Technical University, Brehova 7, 115 19 Prague, Czech Republic
* dorosh@lst.gpi.ru
ZnSe crystals doped with divalent chromium and iron ions are actively used for the development of widely tunable mid-IR lasers. Recently, noticeable progress in the maximal output power and efficiency of these lasers was achieved. An output power in excess of 10 W with an efficiency of over 40% and a pulsed energy of over 1 J were demonstrated for ZnSe:Fe2+ [1,2]. The main disadvantage of Fe2+-based lasers is the need for relatively complex pump sources operating around 3 ^m. One of the alternatives to the development of new simple and efficient pump sources might be the utilization of Cr2+ co-doping of known Fe2+ doped matrices, and the pumping of chromium ions by a number of commercially available pump sources within the 1500-2300 nm range together with fast nonradiative transfer of excitation energy to iron ions. The possibility of quite efficient Cr2+^Fe2+ energy transfer in ZnSe crystal was discussed earlier, but strong competition with Fe2+ ion fluorescence quenching by Cr2+ ions [3] has not yet permitted the lasing of Fe2+ ions in this particular crystal. However, such lasing has already been demonstrated for ZnSe-based solid solutions of Zn1_xMnxSe and Zn1_xMgxSe type co-doped with Cr2+ and Fe2+ ions [4].
The possible formation of Cr2+ and Fe2+ clusters and the influence of such clustering on the TM ion spectroscopic properties have been previously discussed. Similar Cr2+-Fe2+ clusters will be shown to form in this study. Their strong influence on both Cr2+ ions spectroscopic properties and, consequently, the Cr2+^Fe2+ energy transfer process will be presented. As an example, Fig.1 illustrates the position of the Cr2+ ions absorption maximum across a wide temperature range for Cr2+-only-doped and Cr2+,Fe2+-co-doped Zn1-xMnxSe solid solutions. A striking difference in the position and temperature behaviour of the Cr2+ ions in co-doped sample (upper graph in Fig.1b) can be easily observed. The process of Cr2+-Fe2+ ions cluster formation, depending on TM ion concentrations, spectroscopic properties, and their influence on Cr2+^Fe2+ energy transfer and Fe2+ ions fluorescence quenching, will be presented and discussed.
Zni-x' ▲ _JB J Cr2+ x=0 (Z nSeJi x=t .05
>M ♦KM f* x= 0.3 a)
50 100 150 200 250 300 350 400 Temperature, K
5750
5700
E 5650
o 5600 c
0}
¡7 5550 u lire 5500
S 5450
5400
5350
¿^ a.. Zn1_xMnxSe:Cr2î,Fe2+ (x=0.3)
...........
O-O-G-G-e-O-
~crcrtTC3T3
ere
50 100 150 200 250 300 350 400 Temperature, K
Fig.1. Position of Cr2+ ions absorption maximum at different temperatures in Zni-xMnxSe crystal doped only with Cr2+ ions (a)
and in Cr2+,Fe2+ co-doped crystal (b).
5700
5600
5500
5400
b)
This work was supported by Russian Science Foundation Project № 23-22-00236.
[1] S.B. Mirov, et al, Frontiers of Mid-IR Lasers Based on Transition Metal Doped Chalcogenides, in IEEE Journal of Selected Topics in Quantum Electronics, vol. 24, no. 5, pp. 1-29, Sept.-Oct. 2018, Art no. 1601829.
[2] K.N. Firsov, et al, Laser on single-crystal ZnSe:Fe2+ with high pulse radiation energy at room temperature, Laser Phys. Lett. 13 015002 (2016).
[3] V. Fedorov, et al, Energy transfer in iron-chromium co-doped ZnSe middle-infrared laser crystals, Opt. Mater. Express 9, 2340-2347 (2019).
[4] A. Riha, et al, Diode-pumped Cr-doped ZnMnSe and ZnMgSe lasers, Proc. SPIE 10603, Photonics, Devices, and Systems VII, 1060312 (1 December 2017).
